<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>弹性盒子布局</title>
    <style>
        .box{
            display: flex;
            flex-direction: row;
            /* justify-content: space-around;
            align-items: center; */
        }

        .box{
            width: 500px;
            height: 400px;
            border: 1px solid blue;
        }

        .box1,.box2,.box3{
            width: 100px;
            height: 100px;
            border: 1px solid red;
            flex-grow: 1;
        }
       
    </style>
</head>
<body>
    <div class="box">
        <div class="box1">元素一</div>
        <div class="box2">元素二</div>
        <div class="box3">元素三</div>
    </div>
</body>
</html>